Movable-mechanical-section controlling device, method of controlling movable mechanical section, and program

ABSTRACT

A movable-mechanical-section controlling device includes a pan/tilt driving controlling unit configured to perform driving control on a movable mechanical section having a structure that moves so that an image pickup direction of an image pickup section that obtains an image-pickup image by performing an image pickup operation changes in a pan direction and a tilt direction. In the controlling device, unit pan operations that are performed in an angular range in the pan direction are performed for the respective two or more different tilt positions with decreasing angle of elevation at the tilt positions.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a movable-mechanical-sectioncontrolling device that drives and controls a movable mechanicalsection, such as a pan head, on which an image pickup device is placed,for, for example, object search; and to a method of controlling themovable mechanical section. The present invention also relates to aprogram that is executed by the movable-mechanical-section controllingdevice.

2. Description of the Related Art

Japanese Unexamined Patent Application Publication No. 2001-268425discusses, as an automatic tracking mechanism, a structure of a remotecontrol pan head system that accommodates a television camera. That is,the document discusses a system configuration or a device that canautomatically perform an object search operation by a combination of animage pickup device section and a pan head.

SUMMARY OF THE INVENTION

It is desirable to make it possible to perform a search operation asefficiently as possible when an image pickup device or an image pickupsystem that is formed so as to be capable of changing an image pickupdirection of an image pickup section is caused to automatically detector search for an object.

According to an embodiment of the present invention, there is provided amovable-mechanical-section controlling device including pan/tilt drivingcontrolling unit means for performing driving control on a movablemechanical section having a structure that moves so that an image pickupdirection of an image pickup section that obtains an image-pickup imageby performing an image pickup operation changes in a pan direction and atilt direction. In the controlling device, unit pan operations that areperformed in an angular range in the pan direction are performed for therespective two or more different tilt positions with decreasing angle ofelevation at the tilt positions.

In the above-described structure, search operations that are performedat the tilt positions within the angular range in the pan direction areperformed for the respective tilt positions that differ from each otherin the order in which the image pickup direction is set from an upwardlyoriented state to a downwardly oriented state. That is, the searchoperations in the horizontal direction are performed by a predeterminednumber of times from the upper side to a lower side.

For example, when such search operations are performed, if it is assumedthat there is a high probability that an object exists at a positionwhere the image pickup direction is oriented upward, the probabilitywith which the object is quickly fitted in an image pickup viewing anglerange is high.

Accordingly, the present invention makes it possible to search for anobject more efficiently than before, such as the time until an object isfound being capable of being reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are, respectively, a simple external front view and asimple external back view of a digital still camera, which is an imagepickup device of an image pickup system according to an embodiment ofthe present invention;

FIG. 2 is an exemplary external perspective view of a pan head of theimage pickup system according to the embodiment;

FIG. 3 is a front view of an example in which the digital still camerais mounted to the pan head in the image pickup system according to theembodiment;

FIG. 4 is a plan view of the example in which the digital still camerais mounted to the pan head in the image pickup system according to theembodiment, and exemplary movements in a pan direction;

FIG. 5 is a side view of the example in which the digital still camerais mounted to the pan head in the image pickup system according to theembodiment;

FIG. 6 is a side view of the example in which the digital still camerais mounted to the pan head, and exemplary movements in a tilt direction;

FIG. 7 is a block diagram of an exemplary configuration of the digitalstill camera;

FIG. 8 is a block diagram of an exemplary structure of the pan head;

FIG. 9 is a block diagram of an exemplary configuration of an internalsystem for the image pickup system according to the embodiment;

FIG. 10 illustrates the movements in the pan direction as object searchmovements that can be considered;

FIG. 11 illustrates a two-dimensional search pattern as the objectsearch movements that can be considered;

FIG. 12 shows a first exemplary two-dimensional search pattern accordingto the embodiment;

FIG. 13 shows a second exemplary two-dimensional search patternaccording to the embodiment;

FIG. 14 illustrates an operation when an effective search range is notlimited as an object search operation according to the embodiment;

FIG. 15 illustrates an operation when the effective search range islimited to 180 degrees as the object search operation according to theembodiment;

FIG. 16 illustrates an operation when the effective search range islimited to 90 degrees as the object search operation according to theembodiment;

FIG. 17 is a flowchart showing a first exemplary algorithm for automaticimage pickup recording including the object search operation accordingto the embodiment;

FIGS. 18A and 18B are flowcharts of an exemplary processing procedurefor a parameter setting operation and a search angle-of-field settingcontrolling operation in the first exemplary algorithm;

FIG. 19 is a flowchart of an exemplary processing procedure as amodification of the parameter setting operation in the first exemplaryalgorithm;

FIG. 20 shows an exemplary content of a parameter table for rangescorresponding to effective search ranges corresponding to the firstexemplary algorithm;

FIG. 21 shows an exemplary content of a parameter table for rangescorresponding to effective search ranges corresponding to themodification of the first exemplary algorithm;

FIGS. 22A to 22C illustrate an exemplary basic operation in a secondexemplary partial search range setting operation;

FIGS. 23A to 23C illustrate another exemplary basic operation in thesecond exemplary partial search range setting operation;

FIGS. 24A and 24B illustrate an exemplary operation when the effectivesearch range is limited in the second exemplary partial search rangesetting operation; and

FIGS. 25A and 25B illustrate an exemplary operation when the effectivesearch range is limited in the second exemplary partial search rangesetting operation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments for carrying out the invention of the application willhereunder be described in accordance with the following items in thefollowing order:

-   -   <1. Configuration of Image Pickup System>        -   [1-1. Overall Configuration]        -   [1-2. Digital Still Camera]        -   [1-3. Pan Head]        -   [1-4. Exemplary Functional Structure of Image Pickup System]    -   <2. First Exemplary Object Search Movement>    -   <3. Second Exemplary Object Search Movement: Two-Dimensional        Search Pattern In Embodiment>        -   [3-1. First Example]        -   [3-2. Second Example]    -   <4. Third Exemplary Object Search Movement: First Exemplary        Partial Search Range Setting Operation In Embodiment>        -   [4-1. When Rotation Angle Is Not Limited]        -   [4-2. When Rotation Angle Is Limited: Effective Rotation            Angle=180 Degrees]        -   [4-3. When Rotation Angle Is Limited: Effective Rotation            Angle=90 Degrees]    -   <5. Algorithm According to Embodiment>        -   [5-1. Basic Example]        -   [5-1-1. Modification of Parameter Setting]    -   <6. Fourth Exemplary Object Search Movement: Second Exemplary        Partial Search Range Setting Operation>

In the description below, the terms “picture frame,” “angle of field,”“image pickup viewing angle,” and “framing,” will be used.

The term “picture frame” refers to an area range corresponding to onescreen where, for example, an image can be seen as fitted therein. Ingeneral, the picture frame has the shape of an outer frame, which is avertically long rectangular shape or a horizontally long rectangularshape.

The term “angle of field” is also called “zoom angle,” and expresses byan angle a range in which an image is fitted in a picture framedetermined by the position of a zoom lens in an optical system of animage pickup device. In general, the angle of field is determined by thefocal length of the image pickup optical system and the size of an imagesurface (image sensor or film). However, here, the angle of field refersto a factor that can change in accordance with the focal length. Thevalue of the angle of field may hereunder be represented by the focallength (such as a converted value of 35 mm).

The image pickup viewing angle is determined by an angle (angle ofelevation, angle of depression) in a tilt (vertical) direction and arotation angle in a pan (horizontal) direction in addition to the angleof field for the range in which an image, obtained by picking it up bythe image pickup device placed in position, is fitted in the pictureframe.

The term “framing” refers to a disposing state based on, for example,setting of the size of an object in the picture frame determined by theimage pickup viewing angle.

In the embodiment, a structure based on the invention of the applicationis exemplified as being applied to an image pickup system including adigital still camera and a pan head to which the digital still camera ismounted.

1. Configuration of Image Pickup System 1-1. Overall Configuration

An image pickup system according to the embodiment includes a digitalstill camera 1 and a pan head 10 on which the digital still camera 1 isplaced.

First, an exemplary external appearance of the digital still camera 1 isshown in FIGS. 1A and 1B. FIGS. 1A and 1B are, respectively, a frontview and a back view of the digital still camera 1.

First, as shown in FIG. 1A, the illustrated digital still camera 1includes a lens section 21 a at the front side of a body 2. The lenssection 21 a is exposed at the outer side of the body 2 as an opticalsystem for performing an image pickup operation.

A release button 31 a is provided at the top surface of the body 2. Inan image pickup mode, an image (image pickup image) picked up by thelens section 21 a is generated as an image signal. If, in the imagepickup mode, the release button 31 a is operated, the image pickup imagethat is obtained at a timing of this operation is recorded on a storagemedium as still image data. That is, a photograph is taken.

As shown in FIG. 1B, the digital still camera 1 has a display screensection 33 a at the back surface thereof.

In the image pickup mode, the display screen section 33 a displays animage called, for example, a through image and picked up by the lenssection 21 a at this time. In a reproduction mode, the display screensection 33 a reproduces and displays image data recorded on the storagemedium. Further, the display screen section 33 a displays an operationimage for a graphical user interface (GUI) in accordance with anoperation performed by a user on the digital still camera 1.

The digital still camera 1 according to the embodiment is a combinationof a touch panel with the display screen section 33 a. This allows theuser to perform an appropriate operation when the user touches thedisplay screen section 33 a with his/her finger.

The image pickup system (image pickup device) according to theembodiment is one including an image pickup device section, serving asthe digital still camera 1, and a movable mechanical section, serving asthe pan head 10 described below. However, even if the user only uses thedigital still camera 1, the user can take photographs as with anordinary digital still camera.

FIG. 2 is an external perspective view of the pan head 10. FIGS. 3 to 6are each an external view of the image pickup system according to theembodiment in which the digital still camera 1 is properly placed on thepan head 10. FIG. 3 is a front view thereof; FIG. 4 is a plan viewthereof; FIG. 5 is a side view thereof; and FIG. 6 is a side viewshowing a movable range of a tilt mechanism.

As shown in FIGS. 2, 3, 4, and 5, the pan head 10 generally has astructure in which a body section 11 is assembled on a ground tablesection 15, and a camera base section 12 is mounted to the base section11.

When one tries to place the digital still camera 1 on the pan head 10,the bottom surface of the digital still camera 1 is placed on the topsurface of the camera base section 12.

As shown in FIG. 2, here, a projection 13 and a connector 14 areprovided on the top surface of the camera base section 12.

Although not shown, the lower surface of the body 2 of the digital stillcamera 1 has a hole that engages the projection 13. When the digitalstill camera 1 is properly placed on the camera base section 12, thehole and the projection 13 are engaged with each other. In this state,if an ordinary panning/tilting of the pan head 10 occurs, the digitalstill camera 1 is prevented from being displaced or removed from the panhead 10.

A connector is also provided at a predetermined position of the lowersurface of the digital still camera 1. When the digital still camera 1is properly placed on the camera base section 12 as described above, theconnector of the digital still camera 1 and the connector 14 of the panhead 10 are connected to each other, so that at least communicationtherebetween is possible.

For example, the connector 14 and the projection 13 can actually move atthe camera base section 12. Here, by using, for example, an adapterhaving a shape corresponding to the shape of the bottom surface of thedigital still camera 1, a different type of digital still camera in astate that can perform communication with the pan head 10 can be placedon the camera base section 12.

Communication between the digital still camera 1 and the camera basesection 12 may be performed by radio.

While the digital still camera 1 is placed on the pan head 10, astructure in which the digital still camera 1 is charged from the panhead 10 may be used. In addition, a structure in which an image signal(of, for example, an image that is reproduced at the digital stillcamera 1) is also transmitted towards the pan head 10, and is output toan external monitor device from the pan head 10 by, for example, a cableor radio communication may be provided. That is, the pan head 10 may beused not only for changing the image pickup viewing angle of the digitalstill camera 1, but also as a cradle.

The image pickup viewing angle is determined by an angle (angle ofelevation, angle of depression) in a tilt (vertical) direction and arotation angle in a pan (horizontal) direction in addition to the angleof field for the range in which an image, obtained by picking it up bythe image pickup device placed in position, is fitted in the pictureframe.

Next, basic movements in a pan direction and a tilt direction of thedigital still camera 1 caused by the pan head 10 will be described.

First, the basic movement in the pan direction is as follows.

While the pan head 10 is placed on, for example, a floor surface, thebottom surface of the ground table section 13 is grounded. In thisstate, as shown in FIG. 4, the body section 11 can rotate clockwise orcounterclockwise around a rotating shaft 11 a as a rotation center. Bythis, the image pickup viewing angle of the digital still camera 1placed on the pan head 10 changes along a left-right direction(horizontal direction). That is, a panning movement is applied.

In addition, a pan mechanism of the pan head 10 in this case has astructure that allows it to rotate freely without restriction bothclockwise and counterclockwise by 360 degrees or more.

Further, in the pan mechanism of the pan head, a reference position inthe pan direction is determined.

Here, as shown in FIG. 4, with the pan reference position being 0degrees (360 degrees), a rotation position of the body section 11 alongthe pan direction, that is, a pan position is indicated from 0 degreesto 360 degrees.

Next, the basic movement of the pan head 10 in the tilt direction is asfollows.

The movement in the tilt direction is obtained by moving the camera basesection 12 around a rotating shaft 12 a as a rotation center in both anangle-of-elevation direction and an angle-of-depression direction asshown in FIGS. 5 and 6.

Here, FIG. 5 shows a state in which the camera base section 12 is at atilt reference position Y0 (0 degrees). In this state, an image pickupdirection F1, which coincides with an image pickup optical axis of thelens section 21 a (optical system section), and a ground surface sectionGR, to which the ground table section 13 is grounded, are parallel toeach other.

Here, as shown in FIG. 6, first, in the angle-of-elevation direction,the camera base section 12 can move around the rotating shaft 12 a asthe rotation center in a range of from the tilt reference position Y0 (0degrees) to a predetermined maximum rotation angle of +f degrees. Evenin the angle-of-depression direction, the camera base section 12 canmove around the rotating shaft 12 a as the rotation center in a range offrom the tilt reference position Y0 (0 degrees) to a predeterminedmaximum rotation angle of −g degrees. Accordingly, by moving the camerabase section 12 in a range of from the maximum rotation angle of +fdegrees to the maximum rotation angle of −g degrees with the tiltreference position Y0 (0 degrees) as a reference point, the image pickupviewing angle of the digital still camera 1 placed on the pan head 10(camera base section 12) changes along an up-down direction (verticaldirection). That is, a tilting movement is performed.

The external structures of the pan head 10 shown in FIGS. 2 to 6 areonly examples. As long as the digital still camera 1 placed on the panhead 10 can move in the pan direction and the tilt direction, any otherphysical structure or configuration may be used.

1-2. Digital Still Camera

The block diagram of FIG. 7 shows an actual exemplary internal structureof the digital camera 1.

In FIG. 7, first, an optical system section 21 includes, for example, astop and a predetermined number of image pickup lens groups (including,for example, a zoom lens and a focus lens). Light that is incident uponthe optical system section 21 is focused as image pickup light upon alight-receiving surface of an image sensor 22.

The optical system section 21 also includes a driving mechanical sectionfor driving, for example, the zoom lens, the focus lens, and the stop.The operation of the driving mechanical section thereof is controlled bywhat is called camera control operations, such as an automatic exposurecontrol operation, an automatic focusing control operation, and a zoom(angle of field) control operation, which are executed by a controllingsection 27.

The image sensor 22 performs what is called photoelectric conversion inwhich the image pickup light obtained by the optical system section 21is converted into an electrical signal. Therefore, the image sensor 22receives at a light-receiving surface of a photoelectric conversionelement the image pickup light from the optical system section 21, andsuccessively outputs at a predetermined timing signal chargesaccumulated in accordance with the intensity of the received light. Bythis, electrical signals (image pickup signals) corresponding to theimage pickup light are output. Although the photoelectric conversionelement (image pickup element) used as the image sensor 22 is notparticularly limited, for example, a complementary metal oxidesemiconductor (CMOS) sensor or charge coupled device (CCD) may actuallybe used. If a CMOS sensor is used, as a device (part) corresponding tothe image sensor 22, an analog-to-digital converter corresponding to anA/D converter 23 (described below) may also be included.

The image pickup signal output from the image sensor 22 is input to theA/D converter 23, is converted into a digital signal, and is input to asignal processing section 24.

The signal processing section 24 takes in the digital image pickupsignal, output from the A/D converter 23, by, for example, a unitcorresponding to one still image (frame image). By performing apredetermined signal processing operation on the image pickup signal ofa still image unit taken in by the signal processing section 24, thesignal processing section 24 generates image-pickup image data(image-pickup still image data), which is image signal datacorresponding to one still image.

If the image-pickup image data generated by the signal processingsection 24 as described above is recorded as image information on amemory card 40 (which is a storage medium (storage medium device)), forexample, the image-pickup image data corresponding to one still image isoutput to an encode/decode section 25 from the signal processing section24.

The encode/decode section 25 performs a compression encoding operationby a predetermined still image compression encoding method on theimage-pickup image data of a still image unit output from the signalprocessing section 24. Here, for example, in accordance with a controloperation by the controlling section 27, a header or the like is addedso that the encode/decode section 25 converts the image-pickup imagedata into image data compressed to a predetermined form. The image datagenerated in this way is transferred to a media controller 26. Inaccordance with the control operation of the controlling section 27, themedia controller 26 causes the image data that is being transferred tobe written to and recorded on the memory card 40. The memory card 40here is a storage medium having, for example, the external shape of acard in accordance with a predetermined standard, and includes anonvolatile semiconductor storage element, such as a flash memory,therein. The storage medium on which the image data is recorded may beother types of storage media other than the aforementioned memory card.

The signal processing section 24 according to the embodiment is formedso as to use the image-pickup image data obtained as described above,and so as to execute an image processing operation as an objectdetection operation as described below.

The digital still camera 1 executes an image display operation by adisplay section 33 using the image-pickup image data obtained by thesignal processing section 24, so that what is called a through image(which is an image that is currently being picked up) can be displayed.For example, the signal processing section 24 takes in the image pickupsignal output from the A/D converter 23 as previously described, andgenerates the image-pickup image data corresponding to one still image.By continuing this operation, pieces of image-pickup image data eachcorresponding to a frame image in a moving image are successivelygenerated. The pieces of image-pickup image data that are successivelygenerated in this way are transferred to a display driver 32 inaccordance with a control operation of the controlling section 27. Bythis, a through image display is performed.

The display driver 32 generates a driving signal for driving the displaysection 33 on the basis of the image-pickup image data that is inputfrom the signal processing section 24 as described above, and outputsthe driving signal to the display section 33. By this, the displaysection 33 successively displays images based on the pieces ofimage-pickup image data of a still image unit. If the user views thesuccessive display of the images, the images that are picked up at thistime are dynamically displayed on the display section 33. That is,through images are displayed.

The digital still camera 1 can reproduce any piece of image datarecorded on the memory card 40, and display the image on the displaysection 33.

Therefore, the controlling section 27 specifies image data, andinstructs the media controller 26 to read out the data from the memorycard 40. In response to this instruction, the media controller 26accesses an address on the memory card 40 on which the specified imagedata is recorded, reads out the data, and transfers the read out data tothe encode/decode section 25.

In accordance with, for example, a control operation of the controllingsection 27, the encode/decode section 25 takes out subject data ascompressed still image data from the image-pickup image data transferredfrom the media controller 26, so that image-pickup data corresponding toone still image is obtained. Then, the image-pickup image data istransferred to the display driver 32. By this, the display section 33reproduces and displays an image of the image-pickup image data recordedon the memory card 40.

The display section 33 can display a user interface image (operationimage) in addition to, for example, the through image and a reproductionimage of image data. In this case, in accordance with, for example, anoperation state at this time, the controlling section 27 generatesdisplay image data serving as user interface data, and outputs thedisplay image data to the display driver 32. This causes the displaysection 33 to display the user interface image. For example, as on aparticular menu screen, the user interface image can be displayed on adisplay screen of the display section 33 independently of thereproduction image of image-pickup image data and a monitor image. Inaddition, the user interface image may be displayed so that it issuperposed upon or combined with a portion of the monitor image or thereproduction image of the image-pickup image data.

The controlling section 27 actually includes, for example, a centralprocessing unit (CPU), and constitutes a microcomputer along with, forexample, ROM 28 and RAM 29. ROM 28 stores, for example, various piecesof setting information related to the operations of the digital stillcamera 1, in addition to, for example, programs to be executed by theCPU as the controlling section 27. RAM 29 is a primary storage devicefor the CPU.

A flash memory 30 in this case is provided as a nonvolatile storage areaused for storing, for example, the various pieces of setting informationthat are changed (re-written) in accordance with, for example, a useroperation or operation history. If ROM 28 uses, for example, anonvolatile memory such as a flash memory, a portion of a storage areaof ROM 28 may be used in place of the flash memory 30.

An operating section 31 is shown as various operating elements providedin the digital still camera 1, and as an operation information signaloutput member that generates operation information signals (that are inaccordance with operations of these operating elements) and outputs themto the CPU. The controlling section 27 executes predetermined processingoperations in accordance with the operation information signals inputfrom the operating section 31. By this, the operations of the digitalstill camera 1 are executed in accordance with the operations of theuser.

A communication section 34 usable with the pan head is a member thatperforms communication in accordance with a predetermined communicationmethod between the pan head 10 and the digital still camera 1. Forexample, when the digital still camera 1 is mounted to the pan head 10,the communication section 34 includes, for example, a physical layerstructure and a structure for realizing communication in correspondencewith a predetermined layer above the physical layer structure. Thephysical layer structure is provided for making it possible to exchangecommunication signals through wire or by radio between the digital stillcamera 1 and a communication section at the pan head 10. When consideredin correspondence with FIG. 2, as the physical layer structure, aconnector section that is connected to the connector 14 is included.

1-3. Pan Head

The block diagram of FIG. 8 shows an exemplary internal structure of thepan head 10.

As mentioned above, the pan head 10 includes a pan/tilt mechanism. Asmembers corresponding thereto, a pan mechanical section 53, a pan motor54, a tilt mechanical section 56, and a tilt motor 57 are included.

The pan mechanical section 53 includes a mechanism for applying movementin the pan direction (horizontal direction or left-right direction)shown in FIG. 4 to the digital still camera 1 mounted to the pan head10. The movement of this mechanism is obtained by rotation of the panmotor 54 in a forward direction and a reverse direction. Similarly, thetilt mechanical section 56 includes a mechanism for applying movement inthe tilt direction (vertical direction or up-down direction) shown inFIG. 6 to the digital camera 1 mounted to the pan head 10. The movementof this mechanism is obtained by rotation of the tilt motor 57 in aforward direction and a reverse direction.

A controlling section 51 includes a microcomputer formed by assembling,for example, a CPU, ROM, and RAM to each other; and controls themovements of the pan mechanical section 53 and the tilt mechanicalsection 56. When, for example, the controlling section 51 controls themovement of the pan mechanical section 53, the controlling section 51outputs a signal specifying the direction in which the pan mechanicalsection 53 is to be moved and the movement speed thereof to the pandriving section 55. The pan driving section 55 generates a motor drivingsignal corresponding to the input signal and outputs the generated motordriving signal to the pan motor 54. For example, if the motor is astepping motor, the motor driving signal is a pulse signal correspondingto PWM control.

The motor driving signal causes the pan motor 54 to rotate, for example,in a predetermined rotation direction and at a predetermined rotationspeed. As a result, the pan mechanical section 53 is also driven so asto move in a movement direction and at a movement speed corresponding tothose of the pan motor 54.

Similarly, when the movement of the tilt mechanical section 56 is to becontrolled, the controlling section 51 outputs a signal specifying amovement direction and a movement speed for the tilt mechanical section56 to the tilt driving section 58. The tilt driving section 58 generatesa motor driving signal corresponding to the input signal and outputs thegenerated motor driving signal to the tilt motor 57. The motor drivingsignal causes the tilt motor 57 to rotate, for example, in apredetermined rotation direction and at a predetermined rotation speed.As a result, the tilt mechanical section 56 is also driven so as to movein a movement direction and at a movement speed corresponding to thoseof the tilt motor 57.

The pan mechanical section 53 includes a rotary encoder (rotationdetector) 53 a. The rotary encoder 53 a outputs to the controllingsection 51 a detection signal indicating a rotation angle amount of thepan mechanical section 53 in accordance with the rotation of the panmechanical section 53. Similarly, the tilt mechanical section 56includes a rotary encoder 56 a. The rotary encoder 56 a also outputs tothe controlling section 51 a signal indicating a rotation angle amountof the tilt mechanical section 56 in accordance with the rotation of thetilt mechanical section 56.

A communication section 52 is a member that performs communication inaccordance with a predetermined communication method between it and thecommunication section 34 usable with the pan head and disposed in thedigital still camera 1 mounted to the pan head 10. Similarly, thecommunication section 52 includes a physical layer structure and astructure for realizing the communication in correspondence with apredetermined layer above the physical layer structure. The physicallayer structure is provided for making it possible to exchangecommunication signals through wire or by radio with the communicationsection 34 of the digital still camera 1. In FIG. 2, as the physicallayer structure, the connector 14 of the camera base section 12 isincluded.

1-4. Exemplary Functional Structure of Image Pickup System

Next, the block diagram of FIG. 9 shows a functional structure (systemconfiguration) realized by hardware and software (program) for the panhead 10 and the digital still camera 1 of the image pickup systemaccording to the embodiment.

In FIG. 9, the digital still camera 1 includes an image pickup recordingblock 61, a framing determining block 62, a pan/tilt/zoom control block63, and a communication control processing block 64.

The image pickup recording block 61 is a member that obtains an imageobtained by an image pickup operation as image signal data (image-pickupimage data), and executes a control operation for storing theimage-pickup image data on the storage medium. This member includes, forexample, an optical system for an image pickup operation, an imagepickup element (image sensor), a signal processing circuit thatgenerates the image-pickup image data from a signal output from theimage pickup element, and a recording control/processing system forwriting the image-pickup data to and recording (storing) it on thestorage medium.

The recording (image pickup recording) of the image-pickup image data inthe image pickup recording block 61 in this case is executed by aninstruction and a control operation of the framing determining block 62.

The framing determining block 62 takes in the image-pickup image dataoutput from the image pickup recording block 61 for input thereto. Onthe basis of the image-pickup image data, the framing determining block62 first detects an object, and finally executes an operation fordetermining framing. Then, a framing matching control operation forobtaining image-pickup image data indicating the content of an imageobtained by the determined framing is also executed.

Here, an object detecting operation (including setting of an initialface frame) executed by the framing determining block 62 can be executedby the signal processing section 24 in FIG. 7. The object detectionoperation by the signal processing section 24 can be executed as animage signal processing operation by a digital signal processor (DSP).That is, it can be executed by a program or an instruction provided tothe DSP.

Correction of a face frame, determination of a framing, and controllingof framing matching, executed by the framing determining block 62, canbe executed as operations that the CPU serving as the controllingsection 27 executes in accordance with a program.

The pan/tilt/zoom control block 63 performs a pan/tilt/zoom controloperation so that an image-pickup viewing angle and a framingcorresponding to an optimal framing that has been determined areobtained in accordance with an instruction of the framing determiningblock 62. That is, for controlling the frame matching, for example, theimage-pickup viewing angle and the framing to be obtained in accordancewith the optimal framing that has been determined are specified to thepan/tilt/zoom control block 63. For orienting the digital still camera 1in an image pickup direction in which the specified framing and imagepickup viewing angle are obtained, the pan/tilt/zoom control block 63determines a movement amount of the pan/tilt mechanism of the pan head10, and generates a pan/tilt control signal that specifies movementcorresponding to the determined movement amount.

A zoom mechanism included in the image pickup recording block 61 iscontrolled so that, for example, a zoom position for obtaining asuitable angle of field that has been determined is provided, and thezoom mechanism is set at this zoom position.

The communication control processing block 64 is a member for executingcommunication between it and a communication control processing block 71of the pan head 10 in accordance with a predetermined communicationprotocol. A pan/tilt control signal generated by the pan/tilt/zoomcontrol block 63 is transmitted to the communication control processingblock 71 of the pan head 10 by the communication of the communicationcontrol processing block 64.

For example, as shown in FIG. 9, the pan head 10 includes thecommunication control processing block 71 and a pan/tilt controlprocessing block 72.

The communication control processing block 71 is a member for performingcommunication between it and the communication control processing block64 of the digital still camera 1. When the communication controlprocessing block 71 receives the pan/tilt control signal, it outputs thepan/tilt control signal to the pan/tilt control processing block 72.

The pan/tilt control processing block 72 executes a pan/tilt controloperation among the control operations executed by, for example, themicrocomputer (not shown here) of the pan head 10.

In accordance with the input pan/tilt control signal, the pan/tiltcontrol processing block 72 controls a pan driving mechanical sectionand a tilt driving mechanism (neither of which are not shown). By this,panning and tilting are performed for obtaining a horizontal viewingangle and a vertical viewing angle in accordance with the optimalframing.

The framing determining block 62 here executes the object detectionoperation as described below. The pan/tilt/zoom control block 63 canperform a pan/tilt/zoom control operation for searching for the objectin accordance with an instruction.

2. First Exemplary Object Search Movement

As mentioned above, the image pickup system according to the embodimentincluding the digital still camera 1 and the pan head 10 automaticallysearches for an object by a pan/tilt/zoom movement, and detects, forexample, surrounding objects such as human beings. If an object isdetected, a framing setting operation is automatically performed for adetected object, to perform an image-pickup recording operation.

In such an automatic image-pickup recording operation, it is consideredwhat search movement is to be performed when the object search operationis executed, that is, what movement pattern in an image pickup direction(image-pickup optical axis) resulting from panning/tilting is to beprovided.

FIGS. 10 and 11 each show an example of movement that can be consideredwhen an object search operation is carried out.

The movement in the pan direction is as shown in FIG. 10. As indicatedby a first search rotation direction RT1, the pan head 10 is rotated by360 degrees in the clockwise direction. Next, as indicated by a secondsearch rotation direction RT2, the pan head 10 is rotated by 360 degreesin the counterclockwise direction. In this example, the movement in thepan direction is a combination of the movement in the first searchrotation direction RT1 and the movement in the second search rotationdirection RT2.

Here, by combining movements in the tilt direction, the object search isperformed in accordance with a two-dimensional search pattern in whichthe pan head 10 is moved as indicated by white arrows Sc1 to Sc9 in thatorder shown in FIG. 11.

First, here, the search for the object is started in a state in whichthe pan head 10 is positioned at a starting point St corresponding to acertain pan/tilt position. Then, as indicated by the arrow Sc1, the panhead 10 moves from the starting point St to a pan position of 360degrees (0 degrees)/a tilt position of +f degrees, to performpanning/tilting. This pan position of 360 degrees (0 degrees)/tiltposition of +f degrees becomes an origin (search origin P) of the objectsearch operation. As can be understood from FIGS. 4 and 6, at the panposition of 360 degrees (0 degrees)/tilt position of +f degrees, theimage pickup direction F1 is oriented towards a pan standard position inthe pan direction and is oriented upward by an angle of elevation of +fdegrees in the tilt direction.

Next, the pan head 10 moves as indicated by the arrow Sc2. That is, withthe tilt position of +f degrees being maintained, for example, the panhead 10 moves to a pan position of 0 degrees by moving in the secondsearch rotation direction RT2. That is, the pan head 10 rotates by 360degrees in the counterclockwise direction, and returns to the same panposition of 360 degrees (0 degrees).

Next, as indicated by the arrow Sc3, at a pan position of 0 degrees (360degrees), tilting is performed so that the pan head 10 is moved from thetilt position of +f degrees to a tilt position of 0 degrees. By this,the image pickup direction F1 becomes horizontal to the pan referenceposition.

Next, with the pan head 10 being at the tilt position of 0 degrees,panning is performed by 360 degrees in the first search direction RT1 asshown by the arrow Sc4.

Next, as indicated by the arrow Sc5, tilting is performed so that thepan head 10 is moved from the tilt position of 0 degrees to a tiltposition of −g degrees.

Next, as indicated by the arrow Sc6, with the pan head 10 being at thetilt position of −g degrees, panning is performed by 360 degrees in thesecond search rotation direction.

Next, as indicated by the arrow Sc7, with the pan head 10 being at thepan position of 0 degrees (360 degrees), tilting is performed so thatthe pan head 10 is moved from the tilt position of −g degrees to thetilt position of 0 degrees.

Next, as indicated by the arrow Sc8, with the tilt position of 0 degreesbeing maintained, panning in which the pan head 10 is rotated by 360degrees in the first search rotation direction RT1 is performed.

Next, as indicated by the arrow Sc9, with the pan position of 360degrees (0 degrees) being maintained, tilting is performed so that thepan head 10 is moved from the tilt position of 0 degrees to the tiltposition of +f degrees.

When the tilting in accordance with the arrow Sc9 ends, the pan head 10has moved completely once in accordance with the search pattern. As canbe understood from FIG. 11, when the pan head 10 has moved completelyonce in accordance with the arrows Sc2 to Sc9, the search has covered360 degrees at the upper side (the tilt position of +f degrees), thecenter (the tilt position of 0 degrees), and the lower side (the tiltposition of −g degrees), and in the vertical directions (+f degrees to−g degrees) at a front side (pan reference position) in the pandirection.

Subsequently, similarly, the panning and the tilting movementscorresponding to the arrows Sc2 to Sc9 are successively executed andrepeated. If, in this process, an object is detected, the digital stillcamera 1 performs a framing matching control operation and executes animage-pickup recording operation. If, for example, the detected objectis picked up and recorded for providing the necessary number ofphotographs using a proper framing, the pan head 10 returns to the panposition of 360 degrees (0 degrees)/tilt position of +f degrees, whichis the search origin P, to repeat the object search operation inaccordance with the pattern including the movements indicated by thearrows Sc2 to Sc9.

3. Second Exemplary Object Search Movement Two-Dimensional SearchPattern in Embodiment 3-1. First Example

In this example, the search patterns illustrated in FIGS. 10 and 11 isimproved, to propose a search pattern that can be used to perform anobject search operation more efficiently. A first example thereof isillustrated with reference to FIG. 12.

First, in the search pattern in the example, a horizontal search angle αis set. As illustrated below, the horizontal search angle α can bechanged in accordance with, for example, a pattern of movement in thepan direction. A most basic horizontal search angle α is 360 degrees.

In the search pattern shown in FIG. 12, the center position in thehorizontal search angle α is handled as a horizontal center position H.This horizontal center position H is 0 degrees, and a movable range inthe pan direction is represented as being from +α/2 degrees to 0 degreesto −α/2 degrees.

The search pattern shown in FIG. 12 is as follows. In a detaileddescription of the search pattern here, the horizontal search angle α isset at 360 degrees.

Here, when the pan head 10 is at a certain pan position and a certaintilt position corresponding to a starting point St, searching of anobject is started. Then, as indicated by a white arrow Sc1, the pan head10 moves only in a tilt direction from the starting point St to a tiltposition of +f degrees, with the pan position being maintained. The tiltposition of +f degrees at the pan position situated in correspondencewith the starting position St is a search origin P in this case.

In FIG. 11, an absolute position, that is, the pan position of 360degrees (0 degrees)/tilt position of +f degrees is defined as the searchstarting point P. In contrast, in FIG. 12, the tilt position of +fdegrees at the pan position situated in correspondence with the startingposition St is the search origin P. That is, the pan position at thesearch starting point in the embodiment changes in accordance with theposition of the starting point St.

When, in FIG. 12, the pan head 10 reaches the search origin P, asindicated by a white arrow Sc2, panning in which the pan head 10 ismoved from the horizontal center position H (0 degrees) to −2α degreesis performed with the tilt position of +f degrees being maintained.Next, as indicated by a white arrow Sc3, panning in which the pan head10 is moved from the pan position of −2α degrees to the pan position of+2α degrees (which is the other limit) is performed with the tiltposition of +f degrees being maintained. Next, panning in which the panhead 10 is moved from the pan position of +2α degrees to the horizontalcenter position H (0 degrees) is performed with the tilt position of +fdegrees being maintained.

When the horizontal search angle α is 360 degrees, the movementsindicated by the arrows Sc2 to Sc4 are such that, for example, while thedigital still camera 1 is fixed to the tilt position of +f degrees,first, the pan head 10 is rotated counterclockwise (in the second searchrotation direction RT2) from the horizontal center position, is rotatedclockwise by 360 degrees (in the first search rotation direction RT1),is rotated counterclockwise by 180 degrees, and returns to thehorizontal center position H.

Here, when a search operation in the pan direction is performed whileone prescribed tilt position is being fixed, by the movement indicatedby the arrow Sc3, the pan head 10 moves one way by 360 degrees in theclockwise direction (the first search rotation direction RT1). By themovements indicated by the arrows Sc2 and Sc4, the pan head 10 similarlymoves one way by 360 degrees in the counterclockwise direction (thesecond rotation direction RT2). Therefore, by the movements indicated bythe arrows Sc2, Sc3, and Sc4, the pan head 10 moves completely once in aprescribed rotation angular range in the pan direction. For example,although searching may be carried out by a one-way movement, in theexample shown in FIG. 12, searching may be carried out by two-waymovements to more precisely detect an object.

By the movements indicated by the arrows Sc2 to Sc4, first, thesearching in the pan direction while the pan head 10 is at the tiltposition of +f degrees with the image pickup direction F1 being orientedupward is completed.

Next, as indicated by an arrow Sc5, tilting in which the pan head 10 ismoved from the tilt position of +f degrees to the tilt position of 0degrees is performed with the horizontal center position H (0 degrees)being maintained. This causes the image pickup direction F1 to beoriented towards the center (horizontally) in a vertical direction.

Here, as indicated by arrows Sc6, Sc7, and Sc8, panning of the pan head10 is performed similarly to the panning performed by the movementsindicated by the arrows Sc2, Sc3, and Sc4. By this, the searching in thepan direction by the one two-way movement while the image pickupdirection F1 is oriented towards the center (horizontally) in thevertical direction is completed.

Next, as indicated by an arrow Sc9, tilting in which the pan head 10 ismoved from the tilt position of 0 degrees to the tilt position of −gdegrees is performed with the horizontal center position H (0 degrees)being maintained. This causes the image pickup direction F1 to beoriented downward.

Here, as indicated by arrows Sc10, Sc11, and Sc12, panning of the panhead 10 is performed similarly to the panning performed by the movementsindicated by the arrows Sc2, Sc3, and Sc4. By this, the searching in thepan direction by the one two-way movement while the image pickupdirection F1 is oriented downward is completed.

According to the description given thus far, in the search pattern shownin FIG. 12, first, the pan position obtained at the start of the objectsearch is set as it is as a pan position at the search origin P.

This provides, for example, the following advantages. Here, the panposition of the pan head 10 on which the digital still camera 1 isplaced is not a pan reference position. In addition, in this state, thepan head 10 is placed again to start an object search. In such a case, auser has a high tendency to place again the pan head 10 so that theimage pickup direction F1 of the digital still camera 1 substantiallyfaces the user even if the user is unconscious of it. Considering such acase, as in the embodiment, if the pan position of the pan head 10 atthe start of the object search is set as the pan position at the searchorigin P, first, it is highly probable that the user, who has placed thepan head 10 again, is immediately subjected to a search operation. Incontrast, in the case shown in FIG. 11, if the object search is startedafter returning the pan head 10 to the search origin P set as anabsolute position, it is highly probable that it takes a long time forthe user, who has the pan head 10 again, to be subjected to a searchoperation.

From what has been mentioned above, it is highly probable that humanbeings that become photographic subjects exist near the horizontalcenter position H situated in correspondence with the search origin P inat least the pan direction. Therefore, in the search pattern shown inFIG. 12, when panning is performed for changing the image pickupdirection F1 in the vertical direction, it is performed at thehorizontal center position H.

The invention of the application considered and examined severalsituations, and confirmed that, when the image pickup direction isoriented upward, it is highly probable that the face of a human being,who becomes a photographic subject, exists and is detected within apicture frame. As a general tendency, when the user tries to place thepan head 10 having the digital still camera 1 placed thereon forautomatic photographic recording operations, the place where the panhead 10 is placed is often like a table surrounded by human beings whobecome photographic objects. If the human beings, who becomephotographic objects, are primarily standing, for example, a base havinga height from the chest to the waist is more often used. That is, thefaces of the human beings, who become photographic objects, tend to bepositioned higher than the digital still camera 1.

Therefore, in the search pattern shown in FIG. 12, in a search operationin the pan direction, for example, with the image pickup direction beingoriented upward, first, the search operation in the pan direction isperformed (Sc2, Sc3, Sc4), then, the same search operation is performedat the center (in the horizontal direction) (Sc6, Sc7, Sc8), and at thelower side (Sc10, Sc11, Sc12) in that order. That is, each searchoperation in the pan direction with its corresponding tilt positionbeing fixed is performed while changing tilt positions so that the imagepickup direction F1 is gradually changed from the state in which it isoriented upward to the state in which it is oriented downward.

In this case, the search pattern shown in FIG. 12 is provided so that anobject is efficiently detected as quickly as possible.

Here, the tilt position is fixed at three angles, that is, +f degrees, 0degrees, and −g degrees. However, this is only one example. If it isfixed at two or more angles, the tilt position may be set at anarbitrary number of angles within the range of from +f degrees to −gdegrees. It is not necessary for a plurality of tilt positions that areset to be separated at equal angles. The separation angles may bechanged, so that, for example, the separation angle between the tiltpositions where the image pickup direction F1 is upwardly oriented isless than the separation angle between the tilt positions where theimage pickup direction F1 is downwardly oriented.

3-2. Second Example

FIG. 13 shows a second exemplary two-dimensional search patternaccording to the embodiment, which is a simplified pattern based on thetwo-dimensional search pattern shown in FIG. 12.

Even in FIG. 13, when a movement according to the object search patternis started, as indicated by an arrow Sc1, tilting in which the pan head10 at the horizontal center position H is moved to the tilt position of+f degrees is performed with a pan position corresponding to thestarting position St being set at the horizontal center position H. Thiscauses the image pickup direction F1 to be oriented upward.

Next, as indicated by an arrow Sc2, panning in which the pan head 10 ismoved by 180 degrees to the pan position of −α/2 degrees is performedwith the tilt position of +f degrees being maintained. Next, asindicated by an arrow Sc3, panning in which the pan head 10 is rotatedby 360 degrees from the pan position of −α/2 degrees to the pan positionof +α/2 degrees is performed. By this, the search in the left-rightdirection while the image pickup direction F1 is oriented upward iscompleted. The movements indicated by the arrows Sc2 and Sc3 do notresult in a complete two-way movement. In the first example, themovements in the pan direction for the respective fixed tilt positionsresult in one two-way movement. However, in the second example, forsimplicity, if a one-way search operation in at least either theclockwise direction or the counterclockwise direction is performed, thesearch operation in the pan direction at one fixed tilt position isconsidered as being completed.

Next, as indicated by an arrow Sc4, tilting in which the pan head 10 ismoved from the tilt position of +f degrees to the tilt position of 0zero degrees is performed with the pan position of +α/2 degrees beingmaintained. By this, the image pickup direction F1 is changed from thestate in which it is oriented upward to the state in which it isoriented towards the center. Next, as indicated by an arrow Sc5, panningin which the pan head 10 is moved by 360 degrees from the pan positionof +α/2 degrees to the pan position of −α/2 degrees is performed withthe tilt position being 0 degrees. By this, a search operation in thepan direction with the image pickup direction F1 being oriented towardsthe center in the vertical direction is completed.

Next, as indicated by an arrow Sc6, at the pan position of −α/2 degrees,tilting in which the pan head 10 is moved from the tilt position of 0degrees to the tilt position of −g degrees is performed, so that theimage pickup direction F1 is oriented downward. Next, as indicated by anarrow Sc7, panning in which the pan head 10 is rotated by 360 degreesfrom the pan position of −α/2 degrees to the pan position of +α/2degrees is performed with the tilt position of −g degrees beingmaintained. By this, a one-way search operation in the pan directionwith the image pickup direction F1 being oriented downward is completed.

Next, as indicated by an arrow Sc8, at the pan position of +α/2 degrees,tilting in which the pan head 10 is moved from the tilt position of −gdegrees to the tilt position of 0 degrees is performed. Further, asindicated by an arrow Sc9, at the tilt position of 0 degrees, panning inwhich the pan head 10 is rotated by 360 degrees from the pan position of+α/2 degrees to the pan position of −α/2 degrees is performed again.

Next, as indicated by an arrow Sc10, at the pan position of −α/2,tilting in which the pan head 10 is moved from the tilt position of 0degrees to the tilt position of +f degrees is performed. Further, asindicated by an arrow Sc11, at the tilt position of +f degrees, panningin which the pan head 10 is moved from the pan position of −α/2 degreesto the horizontal center position H (0 degrees) is performed. By this,the pan head 10 has completely moved in accordance with the searchpattern once, and the pan/tilt position returns to the search origin P.

Comparing FIG. 13 with FIG. 12, the amount of movement of thepanning/tilting in accordance with the two-dimensional search patternafter the pan head 10 has moved completely once is less in FIG. 13 thanin FIG. 12. By this, it is possible to reduce the time that the pan head10 takes to move completely once in accordance with the search patternin FIG. 13. Accordingly, it is possible to, for example, search for anobject in a shorter time.

However, in the example shown in FIG. 13, for simplifying the searchpattern, the orientation of the image pickup direction F1 in thevertical direction is changed not at the horizontal center position Hbut at the pan positions of ±α/2 degrees. However, in the embodiment,considering the probability of existence of an object, the image pickupdirection F1 in the vertical direction is considered more important thanthe image pickup direction F1 in the horizontal direction. Therefore,even in FIG. 12, as in FIG. 13, a search operation in the left-rightdirection is performed at the upper side, the center, and the lower sidein that order. In this way, in the second example, the time taken forthe pan head 10 to move completely once in accordance with the searchpattern is reduced and search performance is satisfactory in practicalapplications.

In the first and second examples of the search patterns in theembodiment, correspondences of +α/2 degrees and −α/2 degrees with theactual directions of movements in the pan direction may be reversed.That is, in the previous description of FIG. 12, the pan movementdirection towards the left in the plane of the figure and indicated by,for example, the arrow Sc2 is a counterclockwise direction, and the panmovement direction towards the right in the plane of the figure andindicated by, for example, the arrow Sc3 is a clockwise direction. Incontrast, the pan movement direction indicated by, for example, thearrow Sc2 may be a clockwise direction, and the pan movement directionindicated by, for example, the arrow Sc3 may be a counterclockwisedirection

4. Third Exemplary Object Search Movement First Exemplary Partial SearchRange Setting Operation in Embodiment 4-1. When Rotation Angle Is NotLimited

In the description given thus far, when the pan head is moved completelyonce in accordance with the search pattern in FIG. 12 or FIG. 13 in theembodiment, the maximum movement range in the pan direction, that is,the horizontal search angle α is 360 degrees.

In the embodiment, in order to perform an object search operation moreefficiently, for example, a structure has been proposed in which thehorizontal search angle α is divided by predetermined angles smallerthan 360 degrees, and the search is performed in accordance with thesearch pattern shown in, for example, FIG. 12 or FIG. 13 for everydivided angle of the horizontal search angle α (partial angular value).

In the object search in which the horizontal search angle α is divided,for example, the search pattern shown in FIG. 11 may also be used.However, when the search patterns according to the embodiment shown inFIGS. 12 and 13 are used, the object search operation can be performedmore efficiently. In the description below, for convenience, it isassumed that the actual search pattern shown in FIG. 12 is applied forevery divided angle of the horizontal search angle α.

First, as a most basic example of an object search operation in whichthe horizontal search angle α is divided, an example of a searchoperation in which a rotation angle in the pan direction of the pan head10 is not limited will be described with reference to FIG. 14.

In FIG. 14, a pan angle of 360 degrees is divided into four partialsearch ranges (movable angular ranges in the pan direction), that is, afirst partial search range DV1 to a fourth partial search range DV4.Here, the four partial search ranges are equiangular. That is, theangular range in the pan direction of one partial search range is 90degrees. In addition, the angular range in the pan direction of each ofthe first partial search range DV1 to the fourth partial search rangeDV4 corresponds to the horizontal search angle α.

As mentioned above, in the search pattern shown in each of FIGS. 12 and13 according to the embodiment, the horizontal center position H isdetermined in accordance with the pan position at the start of theobject search operation. Therefore, the horizontal center position H ofeach of the first partial search range DV1 to the fourth partial searchrange DV4 can be set for every 90 degree interval at any pan position inthe pan angular range of from 0 degrees to 360 degrees. However, in FIG.14, for simplifying the figure and the description, the horizontalcenter position H of the horizontal partial search range DV1 is shown ascoinciding with a pan reference position.

As shown in FIG. 14, movements in the object search operation when thefirst partial search range DV1 to the fourth partial search range DV4are prescribed are as follows.

First, in the pan angular range of the first partial search range DV1,the pan head 10 is made to move completely once in accordance with thetwo-dimensional search pattern shown in FIG. 12. At this time, thehorizontal center position H in FIG. 12 corresponds to the pan positionof 0 degrees. +α/2 degrees in FIG. 12 corresponds to the pan position of45 degrees, and −α/2 degrees in FIG. 12 corresponds to the pan positionof 315 degrees. That is, the first partial search range DV1 in this caseis set to an angular position range of from the pan position of 315degrees to (0 degrees) to 45 degrees.

When the pan head 10 is made to move completely once in the firstpartial search range DV1 in accordance with the two-dimensional searchpattern shown in FIG. 12, the pan head is subsequently moved in the pandirection so that the image pickup direction F1 is at the pan positionof 90 degrees. The pan position of 45 degrees is set as in the figure,and corresponds to the horizontal center position H in the pan angularrange of the second partial search range DV2. Here, the pan head 10 ismade to move completely once in the second partial search range DV2 inaccordance with the two-dimensional search pattern shown in FIG. 12.

Subsequently, similarly, the pan head 10 is moved to the pan position of180 degrees, which is the horizontal center position H in the thirdpartial search range DV3, so as to move completely once in the thirdpartial search range DV3 in accordance with the two-dimensional searchpattern shown in FIG. 12. Then, the pan head 10 is moved to the panposition of 270 degrees, which is the horizontal center position H inthe fourth partial search range DV4, so as to move completely once inthe fourth partial search range DV4 in accordance with thetwo-dimensional search pattern shown in FIG. 12.

In this way, the pan head 10 is moved completely once in accordance withthe two-dimensional search pattern through the first partial searchrange DV1, the second partial search range DV2, the third partial searchrange DV3, and the fourth partial search range DV4 in that order, sothat the object search operations for all of the search ranges that canbe searched are performed completely once. Subsequently, the searchoperations in which the pan head 10 is moved completely once inaccordance with the two-dimensional search pattern shown in FIG. 12through the first partial search range DV1, the second partial searchrange DV2, the third partial search range DV3, and the fourth partialsearch range DV4 in that order are repeated.

If, on the basis of the aforementioned search operations, an object isfound at, for example, the pan/tilt position included in the firstpartial search range DV1, for example, the digital still camera 1performs a framing matching control operation to perform an image pickuprecording operation. Then, if, for example, the image pickup recordingoperation for the necessary number of photographs is completed, the panhead 10 is moved to the next second partial search range DV2 to performthe search operation.

4-2. When Rotation Angle is Limited: Effective Rotation Angle=180Degrees

The example shown in FIG. 14 corresponds to that in which the rotationangle (effective search range (effective movable angular range)) in thepan direction of the pan head 10 is not limited. In this case, as can beunderstood from the description of FIG. 14, the image pickup systemconsequentially allows the digital still camera 1 to rotate by 360degrees or more without limit in the pan direction, to search for anobject for performing an image pickup operation. However, considering anactual use of the digital still camera 1, depending upon thecircumstances, rotating the digital still camera 1 without limit may notbe desirable.

For example, when the digital still camera 1 is used at, for example, arestaurant, if the digital still camera 1 is rotated by 360 degrees ormore in the pan direction to search for an object, an image-pickuprecording operation may also be performed on other completely unrelatedpersons at another table.

When, for example, at home, the image pickup system according to theembodiment is placed in front of a television set and an attempt is madeto automatically photograph a family watching an image displayed ontelevision, the television is photographed at the back half portion ofthe image pickup system. Therefore, if the image pickup system searchesfor an object by rotating the digital still camera 1 by 360 degrees ormore in the pan direction, its search operation becomes veryinefficient.

Accordingly, in the embodiment, the maximum angle (effective searchrange) to which the pan head 10 can be rotated in the pan direction forsearching for an object can be limited. In the embodiment, first, a usercan choose whether or not to limit the effective search range andperform a setting operation by operating the digital still camera 1. Ifthe user chooses to limit the effective search range, the user canselect an angle for the effective search range from among a plurality ofchoices. In this case, any number of choices may be provided. Here, thenumber of choices is two, that is, 180 degrees and 90 degrees.

That is, in the embodiment, the user can choose from three choices forthe effective search range, that is, [1] unlimited, [2] limited to 180degrees, and [3] limited to 90 degrees.

When the pan head 10 according to the embodiment is formed to functionas a cradle of the digital still camera 1, an AC adapter, an imagesignal cable, etc., may be connected to the pan head 10.

In a specific example, an AC adapter terminal or image output terminaljacks are provided at the back surface of the pan head 10. When plugsare inserted into the terminal jacks, if the effective search range isunlimited, cables connected to the terminals are improperly routed andare in the way. Therefore, the image pickup system is formed so as to becapable of detecting insertion of any plug into its correspondingterminal jack of the pan head 10, and automatically limits and sets theeffective search range to 180 degrees or 90 degrees if a plug isinserted into its corresponding terminal jack of the pan head 10.

FIG. 15 shows an example of setting partial search ranges correspondingto when the angle of an effective search range VL is limited and set to180 degrees.

In FIG. 15, the effective search range VL of 180 degrees is divided intothree ranges, a first partial search range DV1, a second partial searchrange DV2, and a third partial search range DV3. Accordingly, horizontalsearch angles α of the first partial search range DV1, the secondpartial search range DV2, and the third partial search range DV3 are setto 60 degrees.

If, in accordance with the setting of the partial search ranges shown inFIG. 14, the effective search range VL is simply set to 180 degrees, twopartial search ranges whose horizontal search angles are α=90 degreesare set. However, if the effective search range is limited, a range inwhich an object is to be searched for in the pan direction iscorrespondingly narrowed, as a result of which the time that is takenfor one complete object search in an entire searchable range is reduced.For example, if the search time when the effective search range shown inFIG. 14 is unlimited is reduced by an amount that does not practicallycreate problems, when the effective search range is limited, the objectsearch can be more carefully performed.

Accordingly, when the angle of the effective search range VL is set to180 degrees, as shown in FIG. 15, the number of partial search ranges isthree, which is larger than two, and the horizontal search angle α ofone partial search range is 60 degrees, which is smaller than that inFIG. 14.

The search operation in this case is as follows.

First, in a pan angular range of the first partial search range DV1, thepan head 10 is moved completely once in accordance with thetwo-dimensional search pattern shown in FIG. 12. Here, the horizontalcenter position H in FIG. 12 corresponds to a pan position of 0 degrees,+α/2 degrees in FIG. 12 corresponds to a pan position of 30 degrees, and−α/2 degrees in FIG. 12 corresponds to a pan position of 330 degrees.

When, at the first partial search range DV1, the pan head 10 has beenmoved completely once in accordance with the two-dimensional searchpattern shown in FIG. 12, the pan head is subsequently moved in the pandirection so that the image pickup direction F1 is oriented towards apan position of +60 degrees. The pan position of +60 degrees correspondsto the horizontal center position H in a pan angular range of the secondpartial search range DV2 of this case. Accordingly, at the secondpartial search range DV2, the pan head 10 is moved completely once inaccordance with the two-dimensional search pattern DV2 shown in FIG. 12.

Next, the pan head 10 is moved in the pan direction so that the imagepickup direction F1 is oriented towards a pan position of +300 degrees.The pan position of +300 degrees corresponds to the horizontal centerposition H in a pan angular range of the third partial search range DV3of this case. Accordingly, similarly to the above, at the third partialsearch range DV3, the pan head 10 is moved completely once in accordancewith the two-dimensional search pattern shown in FIG. 12.

Accordingly, by causing the pan head 10 to move completely once inaccordance with the two-dimensional search pattern at the first partialsearch range DV1, the second partial search range DV2, and the thirdpartial search range DV3 in that order, the entire searchable range issearched once. Subsequently, the above-described search operation isrepeated.

If, for example, during the above-described search operation, an objectis found in the first partial search range DV1, for example, asmentioned above, the image pickup system performs a framing matchingcontrol operation, and, then, performs an image-pickup recordingoperation. Then, when, for example, the image-pickup operation for thenecessary number of photographs is completed, the pan head 10 is movedin the second search range DV2 to subsequently perform a searchoperation.

The movements in the partial search ranges may be simply performed inthe clockwise or the counterclockwise direction. More specifically, ifthe movements are performed clockwise, in the case shown in FIG. 15, themovements are performed in the third partial search range DV3, the firstpartial search range DV1, and the second partial search range DV2 inthat order.

However, as mentioned above, an object exists in a pan-positiondirection with high probability at the start of an object searchoperation. Therefore, in the embodiment, the object search operation isstarted from the partial search range where the pan position is situatedin correspondence with the horizontal center position H at the start ofthe object search operation.

4-3. When Rotation Angle is Limited: Effective Rotation Angle=90 Degrees

FIG. 16 shows an example of setting partial search ranges correspondingto when an effective search range VL is set to 90 degrees.

In this case, in the effective search range VL of 90 degrees, onepartial search range DV1 whose horizontal search angle α is 90 degreesis set. In a search operation of this case, at the first partial searchrange DV1, a panning/tilting operation is performed once in accordancewith the search pattern shown in FIG. 12. Then, this search operation isrepeated.

In this case, for example, two partial search ranges DV whose horizontalsearch angles α are 45 degrees may be set in the effective search rangeVL of 90 degrees. Alternatively, it is obviously possible to set threepartial search ranges whose horizontal search angles α are set to 30degrees.

However, in this case, only one partial search range DV is set for, forexample, the following reasons.

At present, wide-angle lenses whose focal lengths are 28 mm (convertedvalue=35 mm) or less are beginning to be widely used even in digitalstill cameras. Therefore, depending upon the angle of field at thewide-angle end of a lens of the digital still camera 1, if thehorizontal search angle α is made too small, the ranges are repeatedlysearched more than necessary. Therefore, a good search result may not befrequently provided. Here, in this example, when, considering such afact, the effective search range VL is set to 90 degrees and is, thus,very narrow, one partial search range having the same horizontal searchangle α is set.

For the same reason, for example, when the previously mentionedeffective search range is 180 degrees, for example, as shown in FIG. 15,the horizontal search angles α are set to 60 degrees instead of settingthe horizontal search angles to 45 degrees or 30 degrees.

5. Algorithm According to Embodiment 5-1. Basic Example

Basic examples of algorithms for performing an automatic image-pickuprecording operation including an object search operation in theembodiment described thus far are described with reference to FIGS. 17to 21.

The flowchart shown in FIG. 17 shows an entire first exemplary algorithmfor performing an object search operation. The operation shown in FIG.17 may been considered as being executed when necessary by eachfunctional member of the digital still camera 1 shown in FIG. 9. Theoperation executed by each of these functional members can be consideredas a control/processing procedure executed when the control section(CPU) 27 shown in FIG. 7 executes a program. This point also similarlyapplies to the flowcharts of subsequent figures.

Until the operation shown in FIG. 17 is started, the effective searchrange is set to any one of the conditions [1] unlimited, [2] limited to180 degrees, and [3] limited to 90 degrees in accordance with theoperation of a user or a detection result of, for example, whether ornot a cable is connected to the pan head 10. Then, for example, if atrigger for starting an automatic image-pickup recording operation inaccordance with, for example, the operation of the user is obtained, thecontrolling section 27 executes Step S101 and the steps subsequent toStep S101.

First, in Step S101, as parameters corresponding to a currently seteffective search range, a horizontal search angle α and the number ofpartial search ranges N are set.

The operation of the Step S101 in the first example is shown in theflowchart of FIG. 18A.

For example, the effective search range that has been set in accordancewith the operation of the user or whether or not a cable is connected tothe pan head 10 is stored in, for example, RAM 29 as effective searchrange setting information.

In Step S201 shown in FIG. 18A, the controlling section 27 refers to theeffective search range information, and recognizes a setting content ofthe currently set effective search range. That is, the controllingsection 27 recognizes whether or not the effective search range is setto [1] unlimited, [2] limited to 180 degrees, or [3] limited to 90degrees.

Next, in Step S202, the controlling section 27 refers to a parametertable for effective search ranges stored in the flash memory 30 or ROM28.

For example, the content of the parameter table for the effective searchranges is as shown in FIG. 20. That is, the parameter table includes,for the effective search ranges, the horizontal search angles α and thevalues of the number of partial search ranges N corresponding to therespective conditions [1] unlimited, [2] limited to 180 degrees, and [3]limited to 90 degrees.

From the parameter table for the effective search ranges, thecontrolling section 27 obtains the horizontal search angle α and thevalue of the number of partial search ranges N corresponding to thesetting of the current effective search range recognized in the StepS101. Then, in Step S203, the horizontal search angle α and the numberof partial search ranges N obtained in the Step S202 are set as objectsearch parameters in a present automatic image-pickup recordingoperation.

In Step S102 shown in FIG. 17, 1 is substituted for a variable n. Then,in Step S103, initialization in which 1 is substituted for a variable mis executed.

The variable n represents the number of a partial search range. In theembodiment, if an object is detected once, image-pickup recordingoperations for different framings are executed a plurality of times(such as approximately three times) on the detected object. Then, thenext object search is performed. The variable m represents the number ofimage-pickup recording operations that are performed for each detectedobject.

In Step S104, zoom control is executed so that a prescribed angle offield for the object search is set.

There are various ways of setting the prescribed angle of field for theobject search. Here, the most basic way is used to set the widest angleof field (hereunder referred to as “wide-angle-end angle”) obtained byan image pickup lens of the optical system section 21. By setting thewide-angle-end angle, the image pickup viewing angular range obtained bythe lens becomes widest, so that the object can be correspondinglyefficiently detected.

FIG. 18B shows an operation for setting the wide-angle-end as an angleof field for the object search as Step S104. In Step S301, thecontrolling section 27 executes the zoom control so that the imagepickup lens is set at the wide-angle end.

In Step S105, pan/tilt control for search an nth partial search rangeDVn is started. That is, the pan/tilt control is executed so that apanning/tilting movement in accordance with the two-dimensional searchpattern, previously described with reference to FIG. 12 or FIG. 13, isobtained in the nth partial search range DVn.

The structure for the pan/tilt control for the two-dimensional searchpattern may be as follows.

In one example, the controlling section 27 (the pan/tilt/zoom controlblock 63) of the digital still camera 1 gives instructions regarding,for example, the pan/tilt movement direction, the pan/tilt movementamount, and the movement speed to the controlling section 51 (thepan/tilt control processing block 72) of the pan head 10 so that panningand tilting are performed in accordance with, for example, the arrowsSc1 to Sc12 forming the two-dimensional search pattern shown in FIG. 12.

In another example, for example, a panning/tilt pattern for objectsearch corresponding to the arrows Sc1 to Sc12 of the two-dimensionalsearch pattern shown in FIG. 12 is stored. Then, the controlling section27 (the pan/tilt/zoom control block 63) of the digital still camera 1gives an instruction to the controlling section 51 (the pan/tilt controlprocessing block 72) of the pan head 10 to move the pan head 10 to a panposition corresponding to a horizontal center position H in the nthpartial search range DVn. Then, the controlling section 27 specifies ahorizontal search angle α and gives an instruction to completely searchfor an object once in accordance with the two-dimensional searchpattern. In accordance with this instruction, the controlling section(the pan/tilt control processing block 72) of the pan head calls out thetwo-dimensional search pattern that is stored, and performs apanning/tilt driving operation. At this time, panning at an anglecorresponding to the specified horizontal search angle α is executed ina movable range in the pan direction. With this structure, even if thedigital still camera 1 is not capable of performing pan/tilt drivingcontrol for the two-dimensional search pattern, the movements for objectsearch in accordance with the two-dimensional search pattern can beachieved by, for example, only giving an instruction to search the nthpartial search range DVn.

In a state in which the pan/tilt movement in accordance with thetwo-dimensional search pattern is obtained at the nth partial searchrange DVn when the Step S105 is started, the controlling section 27waits for the detection of an object in Step S106.

Therefore, the controlling section 27 executes an object detectionoperation by making use of image-pickup image data taken in by theframing determining block 62 (the signal processing section 24). Theobject detection operation uses, for example, a face detectiontechnology, and sets a face frame corresponding to an area of an imageof the face for each detected object as a result of the detection. Forexample, pieces of basic information regarding objects, such as thenumber of objects, the sizes of the objects and the positions of theobjects within picture frames when the objects are detected can beobtained from, for example, the position, the size, and the number offace frames FR. In accordance with the setting of the face frames FR, atthis stage, the center of gravity of each object or the overall centerof gravity of a plurality of objects can be obtained.

Several methods of detecting the face are available. In the embodiment,the method used is not particularly limited to these several methods.However, considering, for example, detection precision and designdifficulty, a method that is considered suitable may be used.

Here, in Step S106, until the object search is completely performed oncein accordance with the two-dimensional search pattern at the nth partialsearch range DVn by the object detection operation, detection of atleast one object is waited for. Here, if it is determined that an objecthas been detected, the process proceeds to Step S107 on. In contrast, ifan object is not detected, the process proceeds to Step S112.

In Step S107, a framing determining operation and framing matchingcontrol in accordance with framing determination results are executed.

When an object has been detected, object information, such asface-frame-FR information (position, size, etc.); the center of gravityof each object and the overall center of gravity; and age, sex, and facedirection (detected as attributes) can be obtained for each detectedobject.

In Step S107, the controlling section 27 (the framing determining block62) executes the framing determining operation for determining anoptimal framing by making use of the aforementioned object information.

By the framing determining operation, for example, whether or not thecenter of gravity of an object exists at a proper position in a pictureframe, or a zoom magnification (magnification of the size of the object)is determined. Information regarding framing determining results of theframing determining operation is given to, for example, thepan/tilt/zoom control block 63.

Accordingly, the pan/tilt/zoom control block 63 executes pan/tilt/zoomcontrol for obtaining an image-pickup viewing angle corresponding to thereceived framing determination results. That is, the framing matchingcontrol is executed.

After the framing matching control has been started in the Step S107, inStep S108, the controlling section 27 (the framing determining block 62)determines whether or not the framing actually determined as an image ofimage-pickup image data at that time is the same as the framingdetermined in Step S107 (for example, whether or not the framing that isactually determined is similar to the framing determined in Step S107 bya certain degree or by a degree that is more than the certain degree).That is, the controlling section 27 determines whether or not theframing is OK.

The digital still camera 1 according to the embodiment can detect atleast a smile of a person as a facial expression of a detected subject(object). Here, the framing determination results may include, forexample, the content for specifying that the subject is smiling. If theframing determination results include the specification that the subjectis smiling in this way, when determining whether or not the framing isOK in Step S108, the detection result regarding whether or not thesubject is smiling is also used.

Here, if, for example, the framing is not OK after waiting for a certaintime in a state in which a pan/tilt/zoom driving operation is performedon the basis of a movement amount that is necessary for the framematching, a determination result that the framing is not OK is obtainedIn Step S108. In this case, the process proceeds to Step S112.

In contrast, if a determination result that the framing is OK isobtained in Step S108, the process proceeds to Step S109.

In Step S109, for example, the controlling section gives an instructionfor performing an image pickup recording operation to the image pickuprecording block 61. In accordance with the instruction, image-pickupimage data obtained at this time is recorded as a still image file onthe memory card 40. When the operation of Step S109 is an operation thatis performed first in accordance with the detection of the subject inthe last Step S106, first, a first piece of image-pickup image data isrecorded for the detected subject.

After incrementation of the variable m in Step S110, the controllingsection 27 determines whether or not the variable m is greater than amaximum value in Step S111. Here, the maximum value with which thevariable m is compared corresponds to the number of times image-pickuprecording is to be performed by changing a framing of a subject detectedonce. For example, if the number of times image-pickup recording is tobe performed is three times, the maximum value here is 3.

If, in Step S111, the variable m is less than or equal to the maximumvalue, and a determination result is no, image-pickup recording for aprescribed number of times has not yet been performed on the detectedsubject. In this case, the process returns to Step S107, and a framingdetermining operation and framing matching control for the nextimage-pickup recording are executed. The frame determining operation forthis time is performed for setting a framing differing from that of theprevious framing determining operation. For example, the orientation ofthe face of a subject for a framing may be set to an orientationdiffering from the previous orientation. In addition, for example, theposition and size of the subject in a picture frame may be changed andset. In the previous operation, it is not necessary for the subject tosmile, but the condition that the subject smiles may be set this time.

If, for every subject that is detected in this way, image-pickuprecording for the prescribed number of times is performed, a pluralityof image-pickup images for different framings of the same subject may berecorded.

As described above, the image-pickup recording is performed for theprescribed number of times on the subject detected once. When theimage-pickup recording for the prescribed number of times ends, adetermination result of “yes” is obtained in the Step S111, and theprocess proceeds to Step S112.

When the process reaches the Step S112, the following cases may occur.One case is that, even if, at the nth partial search range DVn, anobject search is completely performed once in accordance with thetwo-dimensional search pattern, an object is not detected, and thedetection result is “no” in the Step S106. Another case is that, even ifan object is detected and framing matching control is executed, theframing is not OK, and the detection result is “no” in Step S108. Stillanother case is that, image-pickup recording performed on the detectedobject for the prescribed number of times ends, and the determinationresult is “yes” in the Step S111.

In either of these cases, the search with respect to the nth partialsearch range DVn ends, and the present range may be shifted to the nextpartial search range.

Accordingly, after incrementation of the variable n in Step S112, thecontrolling section 27 determines whether or not the variable n isgreater than the number of partial search ranges N in Step S113.

If, in Step S113, the variable n is less than or equal to the number ofpartial search ranges N, and the determination result is “no,” objectsearches have not yet been completely performed once for all of therespective partial search ranges. Therefore, in this case, the processreturns to the Step S103. By this, the object search of the next nthpartial search range is started in accordance with the two-dimensionalsearch pattern. Even if, for example, zooming is performed by theprevious framing matching control when the Step S104 is performed again,resetting is performed so that the angle of field (that is, atelephoto-end angle in this case) for the search is set.

Then, as a result of repeating the operations after returning from theStep S113 to the Step S103, at a certain stage when the object searcheshave been completely performed once for all of the respective partialsearch ranges in accordance with the two-dimensional search pattern, thedetermination result is “yes” in the Step S113. In this case, theprocess returns to the Step S103. By this, the object search from thefirst partial search range DV1 in accordance with the two-dimensionalsearch pattern is started again.

5-1-1. Modification of Parameter Setting

Here, modifications of setting the parameters (the horizontal searchangle α, the number of partial search ranges N) in the Step S101 shownin FIG. 17 will be given.

First, a parameter table for ranges corresponding to effective searchranges having the content shown in FIG. 21 is used instead of theparameter table having the content shown in FIG. 20.

In the parameter table for the ranges corresponding to the effectivesearch ranges shown in FIG. 21, the horizontal search angles α and thenumbers of partial search ranges N for respective settings of theeffective search ranges are shown for when the field-angle value γ atthe wide-angle end of a lens of the optical system section 21 (that is,a wide-angle-end field-angle value) is greater than or equal to apredetermined value and for when the field-angle value γ is less thanthe predetermined value.

The field-angle value γ here is represented by a focal length. Here, thefield-angle value γ of the lens is only an example, and is set as beingeither greater than or equal to 25 mm (focal length: converted value of35 mm) or less than 25 mm.

The content of the parameter table for the ranges corresponding to theeffective search ranges shown in FIG. 21 when the field-angle value γ isgreater than or equal to 25 mm is the same as that in FIG. 20.

In contrast, if the field-angle value γ is less than mm and the rangecorresponding to the effective search range is unlimited, the number ofpartial search ranges N is 3 when the horizontal search angle α is 120degrees. If the range corresponding to the effective search range islimited to 180 degrees, the number of partial search ranges N is 2 whenthe horizontal search angle α is 90 degrees. If the range correspondingto the effective search range is limited to 90 degrees, the number ofpartial search ranges N is 1 when the horizontal search angle α is 90degrees. The horizontal angle α when the range corresponding to theeffective search range is unlimited and that when the rangecorresponding to the effective search range is limited to 180 degreesare greater for the case in which the field-angle value γ is less than25 mm than for the case in which the field-angle value γ is greater thanor equal to 25 mm. The numbers of partial search ranges N arecorrespondingly reduced.

The number of partial search ranges N and the horizontal search angle αcorresponding to one effective search range are changed in accordancewith the wide-angle-end field-angle value of the lens in this way forthe following reasons.

For the lenses of a digital still camera, lenses having a wide angle offield tend to be actually used. As the angles of field of the lenses ofthe digital still camera 1 become very wide, the range in which objectsearch can be performed at a fixed position is also increased. Takingthis into consideration, even if the lenses have angles of field thatare greater than or equal to a certain angle of field, for thehorizontal search angles α and the numbers of partial search ranges Nfor defaults assuming, for example, a telephoto-end angle ofapproximately 35 mm, there are too many areas that are repeatedlysearched for the respective partial search ranges. Therefore, there maybe cases where the object search is not very efficiently performed.

Consequently, in a modification, when a lens having a wide-angle-endfield-angle value γ that is greater than or equal to a certain value isused, the horizontal search angle α is made larger than usual, and thenumber of partial search ranges DV is correspondingly reduced. In theexample shown in FIG. 21, if the effective search range is limited to 90degrees, the number of partial search ranges N is 1 and the horizontalsearch angle α is 90 degrees regardless of the wide-angle-endfield-angle value γ. This is because, for example, when the effectivesearch range is limited to a relatively narrow range of 90 degrees,further increasing the horizontal search angle α is not particularlymeaningful.

The flowchart shown in FIG. 19 indicates an exemplary processingprocedure of the Step S101 shown in FIG. 17 corresponding to amodification of setting the parameters.

In Step S401 shown in FIG. 19, as in the Step S201 shown in FIG. 18A,the controlling section 27 refers to the effective search rangeinformation, and recognizes a setting content of a currently seteffective search range.

Next, in Step S402, the controlling section 27 obtains a wide-angle-endfield-angle value γ of a lens of the optical system section 21. If, forexample, the lens is assembled in the digital still camera 1,information regarding the wide-angle-end field-angle value γ of the lensis held in the flash memory 30 or ROM 28. If the lens is replaceable, aninterchangeable lens holds data regarding its wide-angle-end field-anglevalue γ. Accordingly, in this case, when the controlling section 27 ofthe digital still camera 1 performs communication with, for example, aCPU at the replaceable lens, the wide-angle-end field-angle value γ canbe obtained.

In Step S403, the controlling section 27 refers to the parameter tablefor the ranges corresponding to the effective search ranges shown inFIG. 21. Then, the horizontal search angle α and the number of partialsearch ranges N made to correspond to the setting of the effectivesearch range recognized in the Step S401 and the wide-angle-endfield-angle value γ obtained in the Step S402 are obtained.

In one example, when the wide-angle-end field-angle value γ obtained inthe Step S402 is 24 mm, and the setting of the effective search rangerecognized in the Step S401 is limited to 180 degrees, a horizontalsearch angle α of 90 degrees and the number of partial search ranges Nequal to 2 are obtained as parameters corresponding thereto in StepS402.

Then, in the Step S404, the horizontal search angle α of 90 degrees andthe number of partial search ranges N equal to 2 obtained in the StepS403 are set as parameters for object search in a current automaticimage-pickup recording.

6. Fourth Exemplary Object Search Movement Second Exemplary PartialSearch Range Setting Operation

In the first exemplary partial search range setting operation describedthus far, the rotation angles in the pan direction of 360 degrees, 180degrees, and 90 degrees are equally divided into the first partialsearch range DV1 to an nth partial search range DVn by the samehorizontal search angle α, and are set. In this case, an angular rangein the pan direction is set so as not to overlap the other partialsearch ranges. When searching of one partial search range ends,searching of the next partial search range is performed, so that anangular range in the pan direction does not overlap the other partialsearch ranges.

In contrast, in the second example, the partial search ranges are set asdescribed below.

FIGS. 22A to 22C show how the second exemplary partial search rangesetting operation is carried out, and exemplary movements of objectsearch. Although the digital still camera 1 shown in FIGS. 22A to 22C isplaced on the pan head 10, the pan head 10 is not shown for simplifyingand making it easier to view FIGS. 22A to 22C.

Here, by the pan head 10, the digital still camera 1 executes the objectsearch at a partial search range DV shown in FIG. 22A in accordance withthe two-dimensional search pattern shown in FIG. 12 or FIG. 13. Here,the horizontal search angle α at the partial search range DV is, forexample, 90 degrees.

When the object search is being carried out in the partial search rangeDV shown in FIG. 22A, while the image pickup direction F1 of the digitalcamera 1 is oriented towards a position shown in FIG. 22B, an object HSis detected. It is assumed that image-pickup recording of this object iscompleted.

Here, a pan position corresponding to the image pickup direction F1 whenthe object is detected in FIG. 22B is P1. A partial search range wherethe next object search is performed is set from +45 degrees to −45degrees with the pan position P1 being the horizontal center position H(0 degrees).

FIGS. 23A to 23C show another example of the second exemplary partialsearch range setting operation.

Here, the succession of movements from that in FIG. 23A to that in FIG.23B is the same as the succession of movements from that in FIG. 22A tothat in FIG. 22B.

In the another example, as shown in FIG. 23C, a pan position resultingfrom a rotation of 90 degrees in the pan direction from the pan positionP1 corresponding to the image pickup direction F1 when the object isdetected in FIG. 23B is set to a new horizontal center position H (0degrees). A range of 90 degrees from +45 degrees to −45 degrees with thenew horizontal center position H (0 degrees) being the center in the pandirection is set as the next partial search range DV.

That is, whereas, in the operation shown in FIGS. 22A to 22C, the panposition where the object is detected is set as the horizontal centerposition H of the new partial search range DV, in the operation shown inFIGS. 23A to 23C, the pan position resulting from a rotation in the pandirection by a previously set predetermined angle from the pan positionwhere the object is detected is set as the horizontal center position Hof the new partial search range DV.

Accordingly, in the rotational movements in the pan direction in thesecond example shown in FIGS. 22A to 22C and FIGS. 23A to 23C, the panhead 10 is not moved in a previously divided partial search range DV,but is set at the new partial search range DV by determining the newhorizontal center position H (0 degrees) on the basis of the imagepickup direction F1 when the object is detected. Then, such objectsearch of a newly set partial search range DV is repeated.

By performing the object search in this way, the search is carefullyperformed. Depending upon, for example, surrounding conditions such asthe number of people that are subjects being considerably large, it ispossible to automatically record image-pickup image data having apicture content that is more desirable than that in, for example, thefirst example.

Even in the second example, until an object is detected from the startof the object search, as in, for example, FIGS. 14 and 15 showing thefirst example, after equally dividing the angular range into the firstpartial search range DV1 to an nth partial search range DVn, the objectsearch is completely performed once in accordance with thetwo-dimensional search pattern while successively moving the pan head 10through the partial search ranges. Then, when an object is detected,object searches of the partial search ranges shown in FIGS. 22A to 22Cor FIGS. 23A to 23C are executed. If, for example, an object is notdetected after the object search has been performed by the partialsearch range setting shown in FIGS. 22A to 22C or FIGS. 23A to 23C, theprocess returns to the first exemplary operation for executing objectsearch for each of the divided first partial search range DV1 to an nthpartial search range DVn.

If, in the operation in the second example, the effective search rangeis unlimited, the movements shown in FIGS. 22A to 22C are performedeither clockwise or a counterclockwise.

In contrast, if, for example, as shown in FIGS. 15 and 16, the effectivesearch range is limited to less than 360 degrees, when the partialsearch range DV is set to a position of limit of the effective searchrange, it is necessary to consider how to return to the opposite side inthe pan direction.

Accordingly, exemplary rotational movements when the effective searchrange is limited will be described with reference to FIGS. 24A and 24Band FIGS. 25A and 25B. Here, the angle of the limited effective searchrange VL is 180 degrees, and the horizontal search angle α of thepartial search range DV is 60 degrees.

Here, for the effective search range VL of 180 degrees, with the centerthereof being 0 degrees, a limit position is +90 degrees in theclockwise direction, and a limit position is −90 degrees in thecounterclockwise direction.

FIGS. 24A and 24B and FIGS. 25A and 25B schematically show searchoperations without showing the pan head 10 and the digital still camera1. Here, the rotating shaft 11 a of the body of the digital still camera1 is shown.

Here, first, when the effective search range VL of 180 degrees is beingsearched, as shown in FIG. 24A, an object HS is detected when the imagepickup direction F1 is oriented towards a pan position of −75 degrees,and automatic image-pickup recording ends.

In this case, the horizontal search angle α is 60 degrees. Therefore, inthe second example, the pan position that is in correspondence with theimage pickup direction F1 shown in FIG. 24A is set as a horizontalcenter position H. Accordingly, for the partial search range DV that isset in this case, as shown in FIG. 24B, a search angle (+2/α) of 30degrees in the clockwise direction from the horizontal center position H(−75 degrees) to −45 degrees can be provided. However, in thecounterclockwise direction, a search angle of 15 degrees from thehorizontal center position H (−75 degrees) to −90 degrees can only beprovided.

However, in the operational example in this case, a range of from −45degrees to H (−75 degrees) to −90 degrees is set as the partial searchrange DV, and object search in accordance with the two-dimensionalsearch pattern according to the embodiment shown in FIG. 12 or FIG. 13is executed.

In this case, panning in the clockwise direction from the horizontalcenter position H (−75 degrees) is performed by 30 degrees, and panningin the counterclockwise direction from the horizontal center position H(−75 degrees) is performed by 15 degrees. Therefore, the two-dimensionalsearch pattern in this case is not horizontally symmetrical like thetwo-dimensional search patterns shown in FIGS. 12 and 13, but isasymmetrical instead.

It is assumed that, for example, depending upon the object search at thepartial search range DV shown in FIG. 24B, an object is not detected. Inthis case, the search cannot be performed in the counterclockwisedirection. Therefore, it is necessary to set the partial search range DVby moving the pan head 10 clockwise in accordance with some rule.

Here, it is assumed that a new partial search range DV is set as shownin FIG. 25A. That is, panning is performed so that, if the horizontalcenter position of the partial search range DV set in FIG. 24A is H′, apan position of +45 degrees resulting from a rotation of 120 degrees inthe clockwise direction from a pan position where the horizontal centerposition H′ is situated becomes the horizontal center position H of anew partial search range DV. This makes it possible for the partialsearch range DV to be positioned at an angular range at the oppositeside so as to be symmetrically situated with respect to 0 degrees. Then,object search at the new partial search range DV is executed.

The angle of rotation in the reverse direction for moving the partialsearch range DV is set to 120 degrees. The horizontal search angle α of60 degrees in the partial search range DV in the effective search rangeof 180 degrees is a specific exemplary value that is set consideringthat the partial search range DV after the movement generally becomesthe pan position.

It is assumed that, as a result of performing the object search at thepartial search range DV set in FIG. 25A, an object is not detected.Here, panning movement is performed so that, if, as shown in FIG. 25B,the horizontal center position of the partial search range DV set inFIG. 25A is H′, a pan position of −15 degrees resulting from a rotationof 60 degrees in the counterclockwise direction from a pan positionwhere the horizontal center position H′ is situated becomes a newhorizontal center position H. This makes it possible to position thenext partial search range DV in substantially the vicinity of the frontside near 0 degrees. Then, object search of the partial search range DVwhose range is ±30 degrees (+15 degrees to −15 degrees to −45 degrees)with respect to the pan position of −15 degrees is executed.

By the movements mentioned thus far, a range of from a pan position of+90 degrees to a pan position of +75 degrees is not searched. However,even if panning is not performed from the pan position of +90 degrees tothe pan position of +75 degrees, a necessary image-pickup viewingangular range for the range of from the pan position of +90 degrees tothe pan position of +75 degrees can be obtained on the basis of theangle of field of a lens. Therefore, in this case, even if the range offrom the pan position of +90 degrees to the pan position of +75 degreesis not searched, problems do not particularly arise.

If an object is not detected even if the object search is performed inthe partial search range DV shown in FIG. 25B, for example, after theimage pickup direction F is returned to 0 degrees and temporarilystopped, for example, object search of each partial search range dividedas described with reference to, for example, FIG. 15 is successivelyexecuted until an object is detected.

In the description of the embodiment given thus far, the searchmovements in the respective partial search ranges described in FIG. 14on are described as being performed in accordance with thetwo-dimensional search pattern shown in FIG. 12 or FIG. 13. However,from the viewpoint of the search movements, for example, even if searchmovements are those in a partial search range in which the pan head 10simply moves in the pan direction while a certain predetermined panposition is simply set, the search efficiency is increased compared to,for example, that of the search movements in the pan direction through360 degrees.

In the description of the embodiment given thus far, the processingprocedure shown in each figure in the form of a flowchart is executed inaccordance with a program that the controlling section 27 of the digitalstill camera 1 executes.

However, for example, at least one of the processing procedures shown inthe respective figures in the form of flowcharts may be executed at thepan head 1. However, when main object search, framing determination, andautomatic image-pickup recording control functions are provided in thedigital still camera 1, it is possible to combine various types ofdigital still cameras 1 and pan heads 10, which is advantageous from theviewpoint of versatility.

In the image pickup system according to the embodiment, it is notnecessary for the digital still camera 1 and the pan head 10 to beseparate devices, so that they may be integrated to each other. However,if, as in the embodiment, the digital still camera 1 and the pan head 10are formed as separate devices, the digital still camera 1 can be usedas an ordinary camera.

Although, in the description given thus far, the images that aresubjected to automatic image pickup recording are still images, theimages may be moving images generated from images obtained by imagepickup operations.

As mentioned thus far, at least part of the structure based on theapplication may be realized by causing a CPU or a DSP to execute aprogram.

After such a program is stored in a removable recording medium inaddition to being written to and stored in, for example, ROM at the timeof, for example, manufacture, such a program may be installed (updated)from the recording medium and stored in, for example, the flash memory30 or a non-volatile storage area for the DSP. In addition, such aprogram may be installed by a control operation of a device that isanother host device through a data interface such as USB or IEEE 1394.Further, such a program is stored in a storage device such as a networkserver, and the digital still camera 1 is provided with a networkfunction, so that such a program can be downloaded and obtained from theserver.

The present application contains subject matter related to thatdisclosed in Japanese Priority Patent Application JP 2009-149873 filedin the Japan Patent Office on Jun. 24, 2009, the entire content of whichis hereby incorporated by reference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. A movable-mechanical-section controlling device comprising: pan/tiltdriving controlling means for performing driving control on a movablemechanical section having a structure that moves so that an image pickupdirection of an image pickup section that obtains an image-pickup imageby performing an image pickup operation changes in a pan direction and atilt direction, wherein unit pan operations that are performed in anangular range in the pan direction are performed for the respective twoor more different tilt positions with decreasing angle of elevation atthe tilt positions.
 2. The movable-mechanical-section controlling deviceaccording to claim 1, wherein the pan/tilt driving controlling meansperforms the driving control on the movable mechanical section so that,when the unit pan operation is performed at one of the tilt positionsand, then, the tilt position is moved to the next tilt position wherethe next unit pan operation is performed, the tilt position is moved ata center position of the angular range in the pan direction.
 3. Themovable-mechanical-section controlling device according to claim 2,wherein the pan/tilt driving controlling means sets a pan positionobtained when the unit pan operation for each tilt position is to bestarted as the center position of the angular range in the pandirection.
 4. The movable-mechanical-section controlling deviceaccording to claim 1, wherein the pan/tilt driving controlling meansperforms the driving control on the movable mechanical section so that,when the unit pan operation at one of the tilt positions is to beperformed, the pan operation is performed completely once in onedirection in the angular range in the pan direction.
 5. Themovable-mechanical-section controlling device according to claim 4,wherein the pan/tilt driving controlling means performs the drivingcontrol on the movable mechanical section so that, when the unit panoperation at one of the tilt positions is to be performed, the panoperation is performed completely once in one two-way direction in theangular range in the pan direction.
 6. The movable-mechanical-sectioncontrolling device according to claim 1, wherein the pan/tilt drivingcontrolling means operates to search an object that is picked up by theimage pickup section.
 7. The movable-mechanical-section controllingdevice according to claim 6, wherein the object is a face of a humanbeing.
 8. A method of controlling a movable mechanical section,comprising the step of: performing pan/tilt driving control on a movablemechanical section having a structure that moves so that an image pickupdirection of an image pickup section that obtains an image-pickup imageby performing an image pickup operation changes in a pan direction and atilt direction, wherein unit pan operations that are performed in anangular range in the pan direction are performed for the respective twoor more different tilt positions with decreasing angle of elevation atthe tilt positions.
 9. A program for causing amovable-mechanical-section controlling device to perform the step of:performing pan/tilt driving control on a movable mechanical sectionhaving a structure that moves so that an image pickup direction of animage pickup section that obtains an image-pickup image by performing animage pickup operation changes in a pan direction and a tilt direction,wherein unit pan operations that are performed in an angular range inthe pan direction are performed for the respective two or more differenttilt positions with decreasing angle of elevation at the tilt positions.10. A movable-mechanical-section controlling device comprising: apan/tilt driving controlling unit configured to perform driving controlon a movable mechanical section having a structure that moves so that animage pickup direction of an image pickup section that obtains animage-pickup image by performing an image pickup operation changes in apan direction and a tilt direction, wherein unit pan operations that areperformed in an angular range in the pan direction are performed for therespective two or more different tilt positions with decreasing angle ofelevation at the tilt positions.